Inspection And Adjustment Of Valve Clearance - TOHATSU MFS 25D Service Manual

Maintenance
15) Inspection and Adjustment of Valve
Clearance
• Perform inspection and adjustment of valve
clearances when engine is cold.
• Be sure to perform inspection and adjustment of
valve clearances while the cylinder head bolt is
tightened.
• The No.1 cylinder should be at the top dead
center of the compression stroke.
1. Remove the starter lock cable, recoil starter, belt cover,
and spark plug.
2. Remove the cylinder head cover.
3. Turn the flywheel in the clockwise direction to align the
" I" mark a of the driven pulley 1 with the " " mark b of
the cylinder head.
4. Inspect and adjust the air intake and exhaust valve
clearance of the #1 cylinder.
• Insert a thickness gauge between the end of the valve
2 and adjustment screw 3 c and check the valve
clearance.
• Loosen the lock nut 4 if the clearance is outside the
specified range.
• Adjust the valve clearance with the adjustment screw.
• Tighten the lock nuts.
• Check the valve clearance.
Valve Clearance:
Intake valve : 0.10–0.15 mm (0.0040–0.0060 in)
Exhaust valve: 0.20–0.24 mm (0.0080–0.0095 in)
• When loosening or tightening the lock nut,
fasten the adjustment screw with the valve
clearance driver 5.
• Be sure to use the torque wrench 6.
Lock nut:
7 N · m (5 lb · ft) [0.7 kgf · m]
Valve Clearance Driver 5:
P/N. 3AC-99071-0
Torque Wrench 6:
P/N. 3AC-99070-0
Thickness Gauge 7:
P/N. 353-72251-1
5. Turn the flywheel in the clockwise direction to align the "III"
mark of the driven pulley 1 with the " " mark b of the
cylinder head.
6. Check and adjust No. 3 cylinder's valve clearances in the
same procedure as No. 1 cylinder.
7. Turn the flywheel in the clockwise direction to align the "II"
mark of the driven pulley 1 with the " " mark b of the
cylinder head.
8. Check and adjust No. 2 cylinder's valve clearances in the
same procedure as No. 1 cylinder.
3-20
1 Driven Pulley
3
4
2
5 Valve Clearance Driver (Concaved Tip, Square, Width Between
Two Opposing Sides: 3 mm)
6 Torque Wrench (10 mm tip wrench)
7 Thickness Gauge
3
4
2
4st 25/30 2022